Inhibin-like activity in extracts of rabbit placentae.
Following the demonstration of inhibin activity in the ovary, a search was conducted for such activity in the rabbit placenta. A bioassay was utilized that consisted of 16 hours' incubation of the test substance with cultured rat anterior pituitary cells and determination of gonadotrophins in the recovered media. A crude extract of rabbit placenta had no effect on luteinizing hormone (LH) but a slight and insignificant inhibiting effect on follicle-stimulating hormone (FSH) secretion. Ethanol-extracted low steroid preparation of the rabbit placenta significantly inhibited FSH, but had no effect on LH secretion. On Sephadex G100 chromatography a fraction was identified which had inhibin activity. In a parallel chromatography of human seminal fluid inhibin activity was identified in the same elution volume as that of the rabbit placenta extract. It is suggested that rabbit placenta extract contains a non-steroidal substance that interferes with pituitary secretion of FSH, and that this substance may be inhibin.
D000818:Animals; D001681:Biological Assay; D002850:Chromatography, Gel; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D007265:Inhibins; D007986:Luteinizing Hormone / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000187:drug effects; D010920:Placenta / Q000032:analysis*; D011247:Pregnancy; D011506:Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D013735:Testicular Hormones / Q000302:isolation & purification* / Q000494:pharmacology
D011506:Proteins; D013735:Testicular Hormones; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone